1. Field of the Invention
This invention pertains broadly to air travel. More particularly, the invention pertains to an aircraft designed to take off and land vertically.
2. Description of the Prior Art
It has been proven that air travel is significantly safer than travel over land by motor vehicle. Safety in air flight is not absolute however as a variety of conditions and circumstances affect this mode of transportation. Some factors that contribute to unsafe flight are high speed runs on takeoff, high speed approaches on landing, cross winds during landing or takeoff, wing icing and landings of one and one-half g's or more. While these are not the only factors that contribute to unsafe flight, their elimination would significantly decrease the likelihood of aviation mishaps.
Short takeoff and landing (STOL) aircraft and vertical takeoff and landing (VTOL) aircraft have been proposed to substantially lessen the above-described hazards. A number of these aircraft have been reduced to practice with a high degree of success. For example, helicopters have been able to overcome many of the safety related problems confronting more conventional aircraft. But even the most advanced helicopters are relatively slow. Hybrid aircraft such as the V-22 Osprey, incorporating rotatable engines, have been relatively successful for their purposes but these too are slower than most conventional aircraft. The success of the British designed Hawker Harrier is well known, however fuel consumption during takeoff and landing is high as lift is accomplished by directing engine thrust vertically during these maneuvers.
For these or other aircraft, taking off and landing vertically requires sufficient lift to be developed to overcome the weight of the aircraft. Beside the traditional airfoil, a number of schemes have been set forth to enhance the lift of aircraft.
Upper surface wing blowing is known to improve the lift effect. In this technique high velocity jet engine exhaust gases are expelled over the upper surface of an airfoil. The low pressure region created by the rapidly moving gases adds significantly to the lift of the blown wing. This upper surface blowing may be used in conjunction with extendable trailing edge flaps to direct downwardly the exhaust gases to further increase lift.
The use of an augmenter wing as a lift enhancement device has been the subject of extensive research. In blown wing or other aircraft the augmenter wing would be disposed aft and above the aircraft's main wing to utilize otherwise "lost" airflow.
An additional lift increasing concept was developed by W. R. Custer and has become known as the Custer channel wing. The channel wing creates a venturi effect in which airflow is increased and pressure is dropped. This effect also induces airflow over the outer wing panel roots to increase aircraft lift and stability. To further take advantage of this moving air, the ailerons could be moved toward the wing roots to increase roll control at takeoff and landing.
These lift enhancement techniques are known to have been utilized independently, however a vertical takeoff and landing aircraft capable of high speeds and efficient fuel consumption would most likely require a combination of techniques such as these.